A conventional expansion valve includes, for example, a main body that includes a first valve chamber, a second valve chamber, and a valve hole connecting the first valve chamber and the second valve chamber, and a valve body that includes a first cylindrical main shaft provided in the first valve chamber, a second cylindrical main shaft provided in the second valve chamber, and a constricted portion provided in the valve hole and connecting the first main shaft and the second main shaft to each other. The first valve chamber communicates with the first pipe of a refrigerant circuit via a first opening, and the second valve chamber communicates with the second pipe of the refrigerant circuit via a second opening. When refrigerant flows into the first valve chamber from the first pipe, a portion between the valve body and a valve seat that is an end portion of the valve hole serves as an expansion portion, and the expanded refrigerant flows into the second pipe. When the refrigerant flows into the second valve chamber from the second pipe, the portion between the valve body and the valve seat that is the end portion of the valve hole serves as an expansion portion, and the expanded refrigerant flows into the first pipe (e.g., see Patent Literature 1).